21382331 has 2 divisors, whose sum is σ = 21382332. Its totient is φ = 21382330.

The previous prime is 21382327. The next prime is 21382349. The reversal of 21382331 is 13328312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21382331 - 2² = 21382327 is a prime.

It is a super-2 number, since 2×21382331² = 914408157987122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 21382297 and 21382306.

It is not a weakly prime, because it can be changed into another prime (21382381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10691165 + 10691166.

It is an arithmetic number, because the mean of its divisors is an integer number (10691166).

Almost surely, 2^21382331 is an apocalyptic number.

21382331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21382331 is an equidigital number, since it uses as much as digits as its factorization.

21382331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

The square root of 21382331 is about 4624.1032644179. The cubic root of 21382331 is about 277.5566791673.

The spelling of 21382331 in words is "twenty-one million, three hundred eighty-two thousand, three hundred thirty-one".